PeMPK17 interacts with PeMKK7 and participates in para-hydroxybenzoic acid stress resistance by removing reactive oxygen species

• Published in: Ecotoxicology and environmental safety 2023-09, Vol.262, p.115167-115167, Article 115167
• Main Authors: Niu, Yajie, Li, Junru, Zhao, Ye, Xin, Di, Gao, Xue, Zhang, Shuyong, Guo, Jing
• Format: Article
• Language: English
• Subjects: Allelopathy; Mitogen-activated protein kinase; PeMPK17; Poplar; Reactive oxygen species homeostasis
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2023.115167

Mitogen-activated protein kinase (MAPK) plays a crucial role in plant stress response. Poplar is one of the most important afforestation and timber species and inevitably encounters allelopathy effects during continuous cropping. para-hydroxybenzoic acid (pHBA) is a primary soil allelochemical, which can restrict the growth and biomass of poplar. However, the involvement of MAPKs in the underlying physiological and molecular regulatory mechanisms in response to pHBA stress remains unclear. In this study, PeMPK17, a gene encoding a group D MAPK, was cloned from Populus × euramericana. PeMPK17 protein was localized in both nucleus and plasma membrane. Quantitative real-time polymerase chain reaction analysis demonstrated that PeMPK17 expression in poplar increased when treated with pHBA, PEG, and H2O2. Exogenous pHBA and H2O2 induced PeMPK17 expression mediated by reactive oxygen species (ROS). The transgenic poplar plants overexpressing PeMPK17 demonstrated attenuated phenotypic injury, higher relative water content in leaves, and lower ion leakage under pHBA stress. In transgenic poplar, the activity and expression of antioxidant enzymes including superoxide dismutase, peroxidase, and catalase increased, while the content of H2O2, O2·-, and malondialdehyde decreased. These results suggested that PeMPK17 protects cell membranes from oxidative damage by removing excess ROS. In addition, overexpression of PeMPK17 promoted osmoprotectant accumulation including soluble sugar and free proline, which may aid in the regulation of ROS balance under pHBA treatment. Furthermore, the interaction between PeMPK17 and PeMKK7 was confirmed. Collectively, these data identify the molecular mechanisms and signal pathways associated with PeMPK17 that regulate pHBA response in poplar. [Display omitted] •PeMPK17 is an ortholog of AtMPK17 and is located in the cytoplasm and plasma membrane.•PeMPK17 overexpression alleviates the poplar phenotypic injury induced by pHBA stress.•Exogenous pHBA induces PeMPK17 expression, which is mediated by endogenesis ROS.•PeMPK17 overexpression enhances ROS balance and osmotic adjustment under pHBA stress.•The interaction between PeMKK7 and PeMPK17 is confirmed.